Radial velocities, rotations, and duplicity of a sample of early F-type dwarfs

Abstract

We present new radial and rotational velocities for 595 nearby early F dwarfs, based on digital spectra cross-correlated with individually optimised synthetic template spectra. The selection of optimum templates, the determination of rotational velocities, and the extraction of velocities from the blended spectra of double-lined spectroscopic binaries are discussed in some detail. We find 170 spectroscopic binaries in the sample and determine orbits for 18 double-lined and 2 single-lined binaries, including some spectroscopic triples. 73 stars are listed with too rapid rotation to yield useful radial velocities (i.e. υ sin i > 120 km s-1). We discuss the binary frequency in the sample, and the influence of unrecognised binaries on the definition of clean metallicity groups of young F dwarfs and the determination of their kinematical properties.